Blue-red substantive dye.



NITED STATES PATENT OFFICE.

JOHANN EAMMANN, ERNST DAvmIs, AND WALTER voRsTER, 0F ELBER- FELD,GERMANY, ASSIGNORS TO THE FARBENFABRIKEN OF ELE R- FELD ooMPANY, on NEWYORK, N. Y.

BLUE-RED SUBSTANTIVE DYE.

SPECIFICATION forming part of Letters Patent No. 656,620, dated August28, 1900.

Application filed April 4, 1900. Serial No. 11,455. (No specimens.)

with one molecule of the dioxydinapthylamin disulfonic acid having thefollowing formula:

On using in this process two molecules of di- By concentrated sulfuricacid of 60 Baum it is dissolved, yielding a blue solution, the color ofwhich changes into reddish-violet on the addition of a small quantity ofice, while a dark precipitate is separated therefrom on adding a largerquantity of ice It is also line throughout the whole reaction.

azotized meta'xylidin (which base has the formula:

a new 2120 dyestufi can be prepared, which is distinguished by theproperty of dyeing un= mordanted cotton valuable bluish-red fast shades.In order to produce this dyestufi, we can proceed as follows, the partsbeing by weight: 24.2 parts of meta-xylidin are diaz'otiled in the usualway by means of 5.6 parts of hydrochloric acid of 19 Baum and fourteenparts of sodium nitrite. The solution of the diazo compound thusobtained is stirred while cooling into a concentrated solution of 46.1parts of dioxydinaphthylamin disulfonic acid (having the above-givenformula) which is mixed'with twelve parts of sodium carbonate. Thereaction mass must remain alka= Stirring is continued for about twelvehours until the reaction is finished. The mixture is then heated toabout 80 centigrade and the dyestuff thus produced is precipitated bymeans of common salt, fitered ofi, pressed, dried, and pulverized.

The new coloring-matter represents a brown powder of a metallic luster,soluble in water, with a bluish-red color. It is the sodium salt of anacid having the following formula:

soluble in ammonia, as well as in alcohol, with a red color.

The new dyestufi yields on unmordanted cotton in alkaline baths clearbluish-red fast shades.

Having now described our invention and in 80 which is a brown powder ofa metallic luster,

what manner the same is to be performed, 1 As a new article ofmanufacture the dyewhat we claim as new, and desire to secure by I.stuff being an alkaline salt of an acid having Letters Patent, is l theformula:

In testimony whereof we have signed our names in the presence of twosubscribing witnesses.

I c l soluble in water with a bluish-red color, soluble in concentratedsulfuric acid with a blue color which turns into reddish-violet onadding a small quantity of ice, while a dark precipitate is obtained onthe addition of a larger quantity of ice to the sulfuric-acid solution,soluble in alcohol as well as in ammonia with a red color, dyeingunmordasted cotton in alkaline baths clear bluish-red fast shades,substantially as hereinbefore described.

JOHANN BAMMANN. ERNST DAVIDIS. WALTER VORSTER.

Witnesses:

OTTO KONIG, J. A. RITTERSHAUS.

